| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16h 37m 09.5s |
| Declination | -10° 34′ 01.4″ |
| Apparent magnitude (V) | 2.54 |
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This infrared image from NASA's WISE telescope shows the runaway star Zeta Ophiuchi as it creates a bright shockwave (yellow arc) in an interstellar dust cloud as it zooms through space. |
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| Characteristics | |
| Spectral type | O9 III |
| U−B color index | -0.86 |
| B−V color index | 0.02 |
| Variable type | Gamma Cass. |
| Astrometry | |
| Radial velocity (Rv) | -15 km/s |
| Proper motion (μ) | RA: 13.07 mas/yr Dec.: 25.44 mas/yr |
| Parallax (π) | 7.12 ± 0.71 mas |
| Distance | 458 ly (140 pc) |
| Absolute magnitude (MV) | -3.20 |
| Details | |
| Mass | 20 M☉ |
| Radius | 8 R☉ |
| Luminosity | 68,000 L☉ |
| Temperature | 33,500 K |
| Metallicity | titanium |
| Rotation | 380 km/s. |
| Age | 4 × 106 years |
| Other designations | |
Zeta Ophiuchi (ζ Oph, ζ Ophiuchi) is a star located in the constellation of Ophiuchus. It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines".,[1] along with α Ser (Unukalhai), δ Ser (Qin, Tsin), ε Ser (Ba, Pa), δ Oph (Yed Prior), ε Ser (Yed Posterior) and γ Oph (Tsung Ching).[2]
According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, al-Nasaq al-Yamānī or Nasak Yamani were the title for two stars :δ Ser as Nasak Yamani I and ε Ser as Nasak Yamani II (exclude this star, α Ser, δ Oph, ε Oph and γ Oph)[3]
In Chinese, 天市右垣 (Tiān Shì Yòu Yuán), meaning Right Wall of Heavenly Market Enclosure, refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of ζ Ophiuchi, β Herculis, γ Herculis, κ Herculis, γ Serpentis, β Serpentis, α Serpentis, δ Serpentis, ε Serpentis, δ Ophiuchi and ε Ophiuchi.[4] Consequently, ζ Ophiuchi itself is known as 天市右垣十一 (Tiān Shì Yòu Yuán shíyī, English: the Eleventh Star of Right Wall of Heavenly Market Enclosure), represent the state Han (韓),[5][6][7] together with 35 Capricorni in Twelve States (asterism).
Although ζ Ophiuchi is a hot blue supergiant star it appears reddish due to interstellar dust that absorbs much of blue light. In fact, were it not for this dust, ζ Ophiuchi would shine several times brighter and be among the very brightest visible. ζ Ophiuchi is roughly half way through the initial phase of its stellar evolution and will within the next few million years expand into a supergiant star before ending its life in a spectacular supernova.[8][9]
Discoveries announced in early 2011 show that ζ Ophiuchi is moving through space at 87,000 km/h (54,000 mph), having likely been ejected from orbit around a more massive star that was destroyed in its own supernova blast. Due to this high proper motion in combination with high intrinsic brightness and its current location in a dust-rich area of the galaxy, the star is creating a bow-shock in the direction of motion. This shock has been made visible via NASA's Wide-field Infrared Survey Explorer.[10]
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